No one is judging.. I was just trying to get clarification before I answered the question.
And no question is a stupid question. We were all rookies at some point.
To answer your question.
Yes you can. but there's a couple things to note. Make sure your tow vehicle has a power wire that runs to the trailer. This is part of the 7pin, but it isn't always hooked up for power (Sometimes it is used for reverse lights). Easy way to check, is to drain your trailer battery down a bit so that the monitor shows 3/4 or 1/2. Then plug your 7 pin into your tow vehicle while it's running and go check the trailer monitor again. It should be at full. Now this is strictly cause it is charging from your tv. you'll have to leave it running for a while (~1hr) depending on the battery.
And it also depends on your power usage. If you use lots of lights, stereo, you probably won't make it through the night. I've made it from about 3pm to about 4am the next morning. Now mind you we weren't being very cautious with our usage and had the vent fan running for my son. So with due diligence you could easily last 24hrs if not longer.
Just remember that even if every light, stereo, fan, etc, is turned off there is still a drain on the battery..
Don't leave the trailer plugged into your TV. It will drain your TV battery.
And make sure if you are just letting the TV idle while charging the trailer battery that you leave a TV window down. Ask me how I know. 3hrs of on-star not being able to locate my suv even though it was running with the keys locked in it. Ah the joys of camping in remote areas. At least I only had to walk an hour to get cell service.